Various surgical procedures require accessing a body cavity using a trocar. Typically, a trocar includes an elongate cannula fixedly coupled to a housing that defines a chamber in communication with the inner lumen of the cannula. Once the cannula is positioned within the body cavity, various elongate surgical instruments or tools axially extend into and are withdrawn from the cannula through the proximal end portion of the housing.
In use, it is essential to maintain a substantially closed environment during insertion or withdrawal of the trocar so as to preserve sterility of the treatment site in addition to preventing the escape of liquids and/or insufflation. Typically, a seal element is disposed within the housing in an attempt to provide such an environment. However, the effectiveness of such seals typically diminishes as an instrument is delivered off-axis relative to the cannula because such off-axis delivery results in a disproportionate force being applied to one portion of the seal as opposed to the remainder of the seal. This can result in non-uniform deformation of the seal which can thereby result in contamination of the site and/or escape of liquids and/or insufflation from the cannula.
As such, there remains a need for devices and methods configured to allow for the efficient and reliable off-axis delivery of a surgical instrument to a treatment site.